It looks like you have an extra space in the line:
sudoers_base ou=SUDOers, ou=people,ou=users,o=IRD
It should probably be:
sudoers_base ou=SUDOers,ou=people,ou=users,o=IRD
If that doesn't help, please add the following line to /etc/ldap.conf:
sudoers_debug 2
and try running a command. This should result in debugging info
that may help me determine the problem.
- todd